CareerBliss defines young professionals as employees with less than 10 years of experience in a full-time position.

Why are the young pros in these cities so happy? Hint: it’s not the paychecks.

“Salary has the least impact on happiness for this group,” Heidi Golledge, CareerBliss chief executive, says in an interview with Forbes.

“As professionals begin their careers, they seek a company culture that embraces their individual work style. Our data consistently shows that the work environment, co-workers, and the way one works have the biggest effect on overall happiness.”

Google, Facebook, LinkedIn, HP, IBM and Kaiser Permanente are just a few of the companies located in the California cities on the list.

To determine which U.S. cities have the happiest young pros, CareerBliss asked 45,000 young employees to evaluate 10 factors that contribute to workplace happiness (growth opportunities, compensation, company culture, etc.). The professionals ranked each factor on a five-point scale, and CareerBliss combined the numbers to find an overall happiness level for each respondent. It then sorted respondents by location to find which cities had the happiest workers.